The state conference of the NAACP is calling on the District Attorney's Office to drop all charges against Nathan Christopher Dwight -- the young man on the receiving end of a racist rant from a DeKalb County detective.

11Alive News was the first to report on the videotaped police interrogation in which Detective Michael Hellerman uses a racial slur as he tries to intimidate Dwight into confessing to a carjacking and armed robbery -- crimes he insists he did not commit.

The fallout from the videotape and our special report continues to widen. Two metro Atlanta law enforcement agencies -- the DeKalb County Police Department and the Rockdale County Sheriff's Office -- have launched internal investigations into the conduct of their officers and the use of the racial slur.

Rockdale County Sheriff Eric Levett tells 11Alive News he's ordered an investigation into the agency's handling of the incident. Sheriff Levett says Rockdale County Investigator Tracy Radford was present in the interrogation room when the racial slur was used. The Sheriff says the investigation will check to see if Inv. Radford ever reported the incident to his supervisors.

Sheriff Levett also issued an apology for the incident. "On behalf of the Rockdale Sheriff's Office, I would apologize to Mr. Dwight for those words being said." Sheriff Levett said.

The videotape shows DeKalb County Detective Michael Hellerman threatening an Nathan Dwight with the prospect of being convicted by a "jury full of white people," who will only see him as a "straight-up n*****."

DeKalb County Police Chief Cedric Alexander says any disciplinary action for Det. Hellerman is pending the outcome of the department's internal investigation into the incident.

In 2009, Nathan Dwight was accused of carjacking a woman in DeKalb County and then using that stolen car in a violent armed robbery of a convenience store in Rockdale County.

He was tried, convicted and sentenced to life in prison for the robbery in Rockdale.

Eyewitnesses identified him, even though the robber was wearing a disguise.

Nathan spent more than two years behind bars before DNA evidence found in the stolen car convinced a judge to overturn his conviction.

During a blistering police interrogation, the then 21-year-old adamantly maintained his innocence.

The police, however, were convinced they had their man and turned up the heat in hopes of getting a confession. In stark, unflattering terms, Detective Michael Hellerman paints a picture of Dwight's chances before a jury.

"We're going to get a whole jury -- a whole jury full of white people," Detective Hellerman told an visibly agitated Dwight.

"I'm not confessing to nothing I didn't do," Dwight interjected.

"I'm going to put this picture," Detective Hellerman said, referring to a still image from the security cameras at the convenience store, "...next to your photo lineup and you know what they're going to see? They're going to see a straight-up n*****!"

Dwight sat down with 11Alive's Devin Fehely, saying "Morally, in my eyes, that was wrong. I mean he looked me dead in my face and called me, 'a n****.' It was just blatant."

In the interrogation video you can see a desperate Dwight make one final plea to convince detectives hey had the wrong guy.

"Please. I mean this is my life on the line. I know I didn't do this. And I watch too many movies seeing folks going to jail for 20 and 30 years for some crap they didn't even do," the tape shows Dwight saying.

DeKalb County Police Chief Cedric Alexander said, "It sent a chill up my back that an investigator in this police department would use such language."

11Alive News showed the interrogation video to Chief Alexander and his reaction was a mix of embarrassment and outrage.

"Quite frankly, I shouldn't be the only person upset with this. I think anybody in the judicial system should be absolutely outraged by this," he said.

The jurors at Dwight's original trial saw parts of the videotaped interrogation, but neither the prosecution nor the defense played the segment where Detective Hellerman used the n-word.

Defense attorney Mawuli Davis said, "They needed to see how far this officer would go to get this young man to confess to something that he has always said he did not do."

The tape is controversial to be sure, but the courts have ruled police have lots of leeway in how they talk and what they say to suspects in their custody, allowing them to misrepresent evidence and even to lie, if it helps get a confession.

11Alive News asked Jessica Gabel, a law professor at Georgia State University, to conduct a top-to-bottom review of the case.

"I think he absolutely crossed a line. He crossed a line and implied you're not going to get a fair trial in this town because you're black," she said. "What the police and perhaps the prosecution suffered from in this case was a bit of tunnel vision."

Despite Dwight's case being overturned in Rockdale County he's not in the clear yet. He could still be charged in DeKalb where the carjacking case remains open.

The DeKalb County DA's office has not decided what it intends to do with this case.